Data Management Example

Almost all inventory and monitoring databases include a spatial component. The spatial data are usually represented as point data but may also be represented as line features (as in the case of transects) or polygons (for example, delineating habitat extents). ArcGIS personal geodatabases can be used as containers for both spatial and non-spatial data. The ArcGIS personal geodatabase allows shape files and coverages, representing GPS monitoring data, to be converted into feature classes.

A feature class is a spatial data layer (point, line or polygon) stored in a relational database. In the case of personal geodatabases, the spatial data are stored in Access tables (Figure 1). Spatial tables in Access are identified by their GDB_ prefixes. These tables are managed from ArcGIS, either using ArcCatalog or ArcMap. The spatial tables should not be edited from within Access. The following example was developed from the exotic plant inventory at Herbert Hoover NHS.  For a copy of the data and instructions (with examples) click on HEHO Exotic Plant Geodatabase and instructions. Additional examples of the geodatabases include the deer monitoring geodatabase and graphic and the invasive non-native plant geodatabase and graphic. Other geodatabases are stored on the Network Intranet site.

Figure 1. List of spatial (GDB_) and attribute (tbl) tables in Access.

Most geodatabases in our program follow the same basic design (see Figures 1 & 2). The feature class carries a linking field called LocationID which corresponds to the LocationID stored in the tblLocations table. Records from the inventory and monitoring databases tables can be joined to the feature class through this link. The beauty of this arrangement is that both spatial and non-spatial attribute data can be stored in a single Access file and viewed interactively in an ArcGIS environment (Figure 3). This makes small inventory and monitoring geodatabases extremely portable.

Figure 2. Standardized format of Geodatabase, Location and Period tables, and Lookup tables.

Figure 3. Typical ArcCatalog view of gdb components showing feature datasets, feature classes, and attribute tables.